The invention relates to a method and an apparatus for controlling the brake system of a vehicle.
DE 195 26 659, to which U.S. application Ser. No. 08/663,677 corresponds, discloses a method and an apparatus for controlling the brake system of a vehicle, in which the braking force at the wheels is actively controlled during a braking event according to the way the brake pedal is actuated by the driver. A deceleration regulator is provided for control, and a nominal deceleration value for the vehicle is derived from the way in which the driver operates the brake pedal. This nominal deceleration value is converted by the regulator to a factor representing the braking moment to be applied to the wheel brakes. This factor is in turn adjusted preferably in a braking moment regulator by controlling the brake force at the wheel brakes (e.g., by controlling the brake pressure). In the preferred embodiment a PID (proportional-integral-differential) regulator is used as the this regulator.
The brake system itself has a great influence on the performance of the regulator since the way in which it increases and reduces the brake moment can be very different. In one preferred embodiment a hydraulic brake system is used in which the dynamic differences have an important influence on the controlling action.
DE 43 38 399 A1 discloses a driving speed regulator which on the basis of the difference between a nominal or target speed and the actual speed forms a target deceleration value which is the basis for intervention into the brake system of the vehicle toward sustaining the target speed.
For the brake control, it is desirable to have a driving speed regulator of this kind act on the same deceleration regulator. Due to the abrupt changes in the nominal value generated by the deceleration regulator, which in such a case occur in switching between the various value setting means, the controlling action of the deceleration regulator, and thus the action of the brake control itself, might be perceptibly impaired.
It is the object of the invention to offer a deceleration regulator for controlling the brake system of a vehicle, which is adapted to the requirements of automatic braking of the vehicle in various situations.